Occupant protection systems for use in vehicles are known in the art. One type of protection system includes an actuatable inflatable restraint module, which has an inflatable restraint that is commonly referred to as an air bag. A controller determines whether the air bag module is to be actuated to inflate the air bag within a vehicle occupant compartment.
The air bag module is actuated by the controller upon the occurrence of a predetermined condition for which a vehicle occupant is to be cushioned by the air bag. For example, a sensor senses a vehicle condition indicative of a vehicle crash condition and, in response thereto, the air bag module is actuated.
Other types of occupant protection devices are utilized within occupant protection systems. Examples of such other occupant protection devices include an inflatable knee bolster, an inflatable side curtain, an inflatable headliner, a seat belt lock, a seat belt pretensioner, and a D-ring adjuster. A person of ordinary skill in the art will appreciate that some or all of such occupant protection devices have adjustable actuation variables. Such adjustable variables include deployment timing, deployment profile, etc. It is to be appreciated that even suppression of actuation of an occupant protection device is an adjustable variable.
Turning to a specific example of an adjustable aspect, in certain circumstances, it may be preferable to refrain from actuating a protection device even if a vehicle crash condition occurs. In one example, if an occupant associated with an air bag module is at a location such that deployment of the air bag will not enhance protection of the occupant, actuation of the air bag module does not occur. One example in which an occupant is located such that deployment of the air bag will not enhance protection of the occupant is when the occupant is very near the air bag module. Typically, an occupant who is very near an air bag module is referred to as being within an occupant out-of-position zone. Actuation of the air bag module for an occupant who is within the occupant out-of-position zone will not enhance protection of the occupant. Another example of an adjustable aspect is to suppress actuation of the protection device (e.g., an air bag module or a pretensioner module) when an occupant is not located on an associated seat.
A protection system that provides for control of a protection device (e.g., an air bag module) in response to sensed condition(s) (e.g., occupant presence, type or location) beyond merely a sensed crash condition is commonly referred to as a "smart" protection system. Control within such smart protection systems is associated with a rather large volume of information processing and decision-making. In other words, a processor algorithm within a smart protection system can be rather complex.
Recently, distributed occupant protection systems have been developed to address the issues of the increasing numbers of protection devices within a vehicle and the increasing numbers of sensory devices used to gather information for the control of the plurality of protection devices. A central control/sensing unit of such a distributed system receives/derives sensory information. The sensory information is processed and determinations regarding protection device control are made. Command signals are output from the central unit over a bus to the plurality of protection devices. Thus, the processing capability of the central unit must be relatively large. Further, as complexity and sophistication of occupant protection systems grow, the ability of the central processing units must correspondingly grow.